I don't know if someone where to attempt to turn that aircraft carrier into a launch platform it's only following the precedent already set by Boeing and Sealaunch.

Sealaunch is probably a better way of going about off shore launches realistically. I think that carrier would make a better nightclub/entertainment facility.

As far as costs and such go I think that for some teams there just wouldn't be any additional costs. Canadian Arrow might even save money by not needing to transport their ship from the shore to the launch platform.